feat(scenes): rich scene descriptions and control viewer window

Add TipTap editing in the editor and an Electron window on the control panel to read the current scene description.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/renderer/control/ControlApp.module.css

@@ -79,6 +79,98 @@
   justify-content: center;
 }
 
+.bookIcon {
+  display: block;
+  color: var(--text-muted-on-dark);
+}
+
+.modalBackdrop {
+  position: fixed;
+  inset: 0;
+  z-index: var(--z-modal-backdrop);
+  border: none;
+  padding: 0;
+  margin: 0;
+  background: var(--color-scrim);
+  cursor: default;
+}
+
+.modalDialog {
+  position: fixed;
+  z-index: var(--z-modal);
+  left: 50%;
+  top: 50%;
+  transform: translate(-50%, -50%);
+  width: 520px;
+  max-width: calc(100vw - 32px);
+  border-radius: var(--radius-lg);
+  border: 1px solid var(--stroke);
+  background: var(--color-surface-elevated);
+  box-shadow: var(--shadow-xl);
+  padding: 16px;
+  display: grid;
+  gap: 12px;
+}
+
+.descriptionViewDialog {
+  width: min(720px, calc(100vw - 32px));
+  max-height: calc(100vh - 48px);
+  grid-template-rows: auto 1fr auto;
+}
+
+.modalHeader {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+}
+
+.modalTitle {
+  font-weight: 900;
+  font-size: var(--text-lg);
+}
+
+.modalClose {
+  border: none;
+  background: var(--panel2);
+  color: var(--text2);
+  border-radius: var(--radius-sm);
+  width: 34px;
+  height: 34px;
+  cursor: pointer;
+  font-size: 18px;
+  line-height: 1;
+}
+
+.modalFooter {
+  display: flex;
+  justify-content: flex-end;
+  gap: 10px;
+  margin-top: 4px;
+}
+
+.descriptionViewBody {
+  min-height: 360px;
+  max-height: min(560px, calc(100vh - 200px));
+  overflow: auto;
+  padding: 14px 16px;
+  border-radius: var(--radius-md);
+  border: 1px solid var(--stroke);
+  background: var(--color-overlay-dark-3);
+}
+
+.descriptionViewProse {
+  color: var(--text0);
+  font-size: var(--text-md);
+  line-height: 1.55;
+  word-break: break-word;
+}
+
+.descriptionViewEmpty {
+  color: var(--text2);
+  font-size: var(--text-sm);
+}
+
 .radiusRow {
   display: grid;
   grid-template-columns: 100px 1fr 44px;